Boiler feed recycling valve combined with a boiler water level control valve



Feb. 20, 1951 H. J. CAMPBELL 2,542,624

- BOILER FEED RECYCLING VALVE COMBINED WITH A BOILER WATER LEVEL CONTROLVALVE Filed July 21, 1947 W 1v m W BY M ATTORNEY Patented Feb. 20, 1,951

UNITED STATES PATENT OFFICE Y BOILER FEED RECYCLING vALyEiooM- B'INEDwrrn A BOILER WATER LEVEL CONTROL VALVE H. John Campbell, Arlington, Ya.Application July '21, 1947, Serial No. 762,310

-acia ms. (01. 1 37-153) The present invention relates to -a recyclingvalv for'boiier feed water and more particularly to an automatic valveadapted to he controlled by the needs of the boiler and to recycleaportion of the water to the iced pump suction. When the flow to theboiler is out off the water is recycled in order to prevent flashing ofthe water in the pump and burning out of thepump, zloy maintaining acontinuous how of water therethrough.

It is normal to use an 'automati-cval-v-e operated by a systemresponsive to the level of-the water in a boiler. Several systems areknown rorpnewma'ti'cally', hydraulically, mechanically or electricallyreciprocating a valve stem responsive to the liquid level in a boiler ata point remote therefrom. It will be understood that-any'such systerncould be used herein, but the invention herein is illustrated-with thecommon pneumaticsystern. In such system the pneumatic-pressure isdeveloped on a diaphragm responsive to the boiler water level whichrecipro'cates the valve stem of the valve of the present invention. Feedpumpspassheated water at high boiler pressuresthrough this valve. Manyboilers feeding steam for engines and turbines used in propulsion suchas steam locomotives and marine power plants er for variable processsteam in stationary installa tions are rapidly varied in operation withthe valve is constantly varied. The stoppage of flow by this valve ismore flexible than any possible control of the feed pump per se, hencewhen the flow stops at the pump -outlet, the pump becomes a hydraulicbrake and the superheated water flashes into steam causing the pump toshake,- resulting in great mechanical strain, warping and burning ofwearing rings and operating-parts. The present valve will modify thewater now allowing a' portion of the water from the pump outlet to berecycled to the pump suction thus allowin continuous flow through thepump, the quantit-y recycled being variable iroma maximum, sufiicientonly to prevent fiashingxat the pump suction, to no recycle how at allwhen sufiicient flow is otherwise present due to demands of the boiler.

,A valve of this type *must 'be highly accurate in flow control andmust, at'the same time, be carefully balanced as Well as -;ruggedl-yconstructed without internal springs, since the valve must operate undercorrosive conditions of high temperature and pressure. 7

It is accordingly a primary object to construct a boiler feed-controlvalve which will maintain continuous and varied fiow"'throu"gh th boilerfeed pump.

. 2 It is a further object to construct the valve 'to maintain theminimum necessary flow by-recycle; It is a further object to construct abalanced valve with these features whereby accurateilow' is maintainedunder high pressures both 'for-n'or mal flow to the -bofilerand recycle,or either.

Referring to the drawings "Fig.- 1 shows an elevation of the valve withparts in section to show internal construction. Figure 2- is a detail ofthe recycling valve stern taken on the line "2-2 of Fig. l. As shown, avalve body to has the usual flanged inlet H leading from the boiler feedpump and outlet "I2 to the boiler. "The outlet licominuhicates with anoutlet chamber is formed by in? ternal partitioning M in the centralportion of the valve b'cdyhaving fiat upper and lower hori zontaisurfaces 15 and H5 which are bored to receive upper i] and lower it!valve seat bush: in gs. A valve stem l9 is centrally mounted toreciprocate upper '20 and lower 21 valve closure heads to firm'se'ats ontheir respective bushings H and #8, thus giving a substantially well bal anced reciprocating closure between inlet H and outlet 12.

The lower part ofthe valve body in opens a flange -22, to whichis bolteda recycling water return ,line '23 for return tothe feed pump sue tion.The pipe 23 has a flangez i mating with and bolted tofiange 22. Theopening ofpipe21$ and flange'fl is restricted and'bored to receive andsupport a bushing 25 mounted concentric with the lower-valv closure head'2 I. Extending downward and threaded or otherwise attached to thebottom of the valve closure head 2-! as t-ojbe coaxial with the valvestem 19 and bushing :25,

- is 'arecycling valve stemZG, constructed tohfe-a'n' extension of steml9 andto form a sliding closure of the recycling outlet bored in'bus-hing'25.

' 1 As shownin Fig. 2 the recycling valve stem '25 has 'SGVGIaTgiOOVGS21 milled "in th periphery thereof so as to all'owwater to pass thru theclosure. The grooves "21' are milled only to ajplfe determined distancefrom the bottom thereof. The valve stem 2 6 rigidly fixed to the lowervalve closure 21 reciprocatestherewith. These valve c1osures20, and 2iare fully seated in the upper Whenthe valve stem 1 9 is depressed to alower position as to open valve closures 2-0 and 2! su-ii'i 'cient toallow a minimum-quantity or water' td pass thru the pump-to the boilers,the valve stem 3 extension 26 will be depressed therewith and will enterthe bushing to a depth sufiicient to cover the tops of the grooves 21thus stopping any recycling flow therethrough.

The upper part of the valve body I opens into an upper flange 28 towhich is bolted a valve bonnet 29 to receive, support and reciprocatethe valve stem I9 extending centrally therein. The valve stem through astuffing box and is tensioned to the closed position by a spring 3iseated at 32 on a cross brace 33 in the bonnet29 bearing at its upperend on an adjusting nut 34 threaded at 35 'to properly tension spring3|. The stem I9 has mounted at its upper end a safety latch 35 adaptedto allow manual displacement of the stem if the automatic control fails.Item 43 is a cross brace into which latch 36 is screwed.

The upper part of the bonnet has a pair of mating flanges 31' betweenwhich is fitted a diaphragm 38 defining an operating chamber 39 forexpansion or contraction with any fluid such as water or air admitted atthe pressure of which is controlled by an extraneous system (not shownresponsive to the level of the water in the boiler. The upper part ofthe stem 19 terminates in a backing-plate H which is mounted directlybeneath for actuation by the diaphragm 38. The stem l9 may additionallyhave mounted thereon an indicator or pointer rod 42 showing the positionof the valve stem.

In operation the stem will be automatically depressed by pressure of theoperating fluid on the. diaphragm to lower the closure heads from theirseats. Simultaneously the stem extension 26 will recede or be lowered inthe bushing below the height of the milled grooves 21 closing flow ofwater through the pipe 23 and water will pass to the boiler throughoutlet pipe 12. When the boiler demand ceases, the stem I9 is raised byspring 3| and the excess pressure on the lower closure 2| which isslightly larger than 20 against i9 is mounted for reciprocationextending through said aligned recycling valve port and carrying aclosure element associated with the end thereof in close proximity withsaid recycling valve port to open and close said valve port uponreciprocation thereof, the position of all valve closures on said valvestem being so critically adjusted in height that lowering of said valvestem a sufflcient distance to substantially open the main valve portswill restrict the flow of fluid through said recycling valve port andwill substantially close said recyclin valve port when the main valveports are sumcientiy open for normal flow.

2. Valve having the structure defined in claim 1 wherein the end of theextended valve stem reciprocates within the recycling valve port tonormally close and prevent fluid flow through said recycling valve portand has a portion cut away to allow fluid flow through said valve portwhen the stem is reciprocated to close the mainvalve ports and to closesaid recycling valve port when reciprocated to allow any substantialflow through said main valve ports.

3. A boiler feed pump recycling valve comprising a valve body supportinginternal partitioning separating inlet and outlet sections, a pluralityof aligned valve ports in said partitioning, a main valve operating stemmounted ior automatic reciprocation through said valve ports responsiveto fluid demand from the valve outlet, a plurality of valve portclosures mounted on said main stem for substantially balancedreciprocat- 1 ing control of the fluid through said ports, a

the decreased pressure on the diaphragm 38 in chamber 39 thus allowingthe closures 20 and 21 to seat. As the stem rises, the grooves 2! instem extension 26 are uncovered by reciprocation above the height of thebushing 25 thus allowing the water to pass along the grooves 21 throughthe bushing 25 and back to the pump suction connected to pipe 23. r

There is thus shown a well balanced valve of rugged construction withoutinternal springs capable of recycling very hot high pressure water. 1Certain modifications will be apparent to one skilled in the art. Forexample. the exact automatic control for reciprocation of the valve maybe varied, the type of valve seat to obtain adequate balance may besomewhat varied and the form and type closure or grooving to efiect re-vcycling, and the construction of the extensionof the main reciprocatingstem may be modified.

1 I claim: 1

- 1. A boiler feed pump recycling valve comprisrecycling valve port inthe valve body, said recycling valve port being vertically aligned withthe nrst mentioned valve ports, a valve stem extending from said mainreciprocating valve 4 stem a sufficient distance to be enclosed withinsaid recycling valve port in all positions of reciprocation of said mainvalve stem, 2. bushing mounted in said recycling valve port fitted aboutand enclosing the lower end of said valve stem extension to support andallow sliding reciprocation thereof, said valve stem having a series oflongitudinal grooves cut parallel to the valve stem axis in the endthereof in the position enclosed within said bushing said groovesextending a longitudinal distance from the end of said valve stemsufficient to lie wholly within said bushing and to prevent fluid flowtherethrough when the stem is in position allowing flow through the mainvalve ports and extending outside of said bushing and communicatin withthe interior of the valve for recycling flow of fluid through saidgrooves when said stem is reciprocated to the opposite position to closesaid main valve ports.

H. JOHN CAMPBELL.

REFERENCES CITED The following references are of record in thefile ofthis patent:

I UNITED STATES PATENTS Number Name Date 1,344,696 Huber June 29, 19204,470,057 Carter Oct. 9, 1923 1,840,228 Elfers Jan. 5, 1932 1,923,788Mastenbrook Aug. 22, 1933 FOREIGN PATENTS Number Country Date 4,510Australia Nov. 3, 1926 8,854 Norway Mar. 15, 1900

